regular expression and unicode utf-8 in python?

I have block of code:( Django code )

        list_temp = []
        tagname_re = re.compile(r'^[\w+\.-]+$', re.UNICODE)
        for key,tag in list.items():
            if len(tag) > settings.FORM_MAX_LENGTH_OF_TAG or len(tag) < settings.FORM_MIN_LENGTH_OF_TAG:
                raise forms.ValidationError(_('please use between %(min)s and %(max)s characters in you tags') % { 'min': settings.FORM_MIN_LENGTH_OF_TAG, 'max': settings.FORM_MAX_LENGTH_OF_TAG})
            if not tagname_re.match(tag):
                raise forms.ValidationError(_('please use following characters in tags: letters , numbers, and characters \'.-_\''))
            # only keep one same tag
            if tag not in list_temp and len(tag.strip()) > 0:
                list_temp.append(tag)

This allow me to put the tag name in Unicode character.

But I don't know why with my Unicode (khmer uncode Khmer Symbols Range: 19E0–19FF The Unicode Standard, Version 4.0).I could not .

My question :

How can I change the above codetagname_re = re.compile(r'^[\w+\.-]+$', re.UNICODE) to adapt my Unicode character.?Because if I input the tag with the "នយោបាយ" I got the message?

please use following characters in t开发者_如何学编程ags: letters , numbers, and characters \'.-_\''

ោ (U+17C4 KHMER VOWEL SIGN OO) and ា (U+17B6 KHMER VOWEL SIGN AA) are not letters, they're combining marks, so they don't match \w.

bobince's answer is certainly correct. However, before you hit that problem there might be another one - is tag definitely a unicode rather than a str? For example:

>>> str_version = 'នយោបាយ'
>>> type(str_version)
<type 'str'>
>>> print str_version
នយោបាយ
>>> unicode_version = 'នយោបាយ'.decode('utf-8')
>>> type(unicode_version)
<type 'unicode'>
>>> print unicode_version
នយោបាយ
>>> r = re.compile(r'^(\w+)',re.U)
>>> r.search(str_version).group(1)
'\xe1'
>>> print r.search(str_version).group(1)

>>> r.search(unicode_version).group(1)
u'\1793\u1799'
>>> print r.search(unicode_version).group(1)
នយ

As another small point, in your regular expression the + in the character class just means that a literal + is also allowed in the sequence of letters and punctuation.

Have a look at the new regex implementation on PyPI:

http://pypi.python.org/pypi/regex

With Python 3 it says:

>>> import regex
>>> regex.match("\w", "\u17C4")
<_regex.Match object at 0x00F03988>
>>> regex.match("\w", "\u17B6")
<_regex.Match object at 0x00F03D08>